<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title>while</title>
		<style>
			#txt{
				width:600px;
				text-align: center;
				margin: auto;
				color:red;
			}
		</style>
		
	</head>
	<body>
		<div id="txt"></div>
		
		<script>
			// i += 2 -> i = i + 2
			for(var i = 0; i < 10; i++){
				for(var j = 0; j < i; j++){					
					document.getElementById("txt").innerHTML += "☆";
				}
				document.getElementById("txt").innerHTML += "<br/>";
			}
		</script>
	</body>
</html>
